View: Fix view item positioning

[pulseview.git] / pv / view / view.cpp

diff --git a/pv/view/view.cpp b/pv/view/view.cpp
index 39a8ef4b07019141d64b61924d1c6da94a930237..5959ff7b3f94f1288e2c02187a47b802da091704 100644 (file)
--- a/pv/view/view.cpp
+++ b/pv/view/view.cpp
@@ -155,7 +155,9 @@ View::View(Session &session, QWidget *parent) :
        next_flag_text_('A'),
        trigger_markers_(),
        hover_point_(-1, -1),
-       scroll_needs_defaults(false)
+       scroll_needs_defaults_(false),
+       saved_v_offset_(0),
+       size_finalized_(false)
 {
        connect(scrollarea_.horizontalScrollBar(), SIGNAL(valueChanged(int)),
                this, SLOT(h_scroll_value_changed(int)));
@@ -280,6 +282,8 @@ const Viewport* View::viewport() const
 void View::save_settings(QSettings &settings) const
 {
        settings.setValue("scale", scale_);
+       settings.setValue("v_offset",
+               scrollarea_.verticalScrollBar()->sliderPosition());
 
        std::stringstream ss;
        boost::archive::text_oarchive oa(ss);
@@ -295,6 +299,9 @@ void View::save_settings(QSettings &settings) const
 
 void View::restore_settings(QSettings &settings)
 {
+       // Note: It is assumed that this function is only called once,
+       // immediately after restoring a previous session.
+
        if (settings.contains("scale"))
                set_scale(settings.value("scale").toDouble());
 
@@ -314,6 +321,13 @@ void View::restore_settings(QSettings &settings)
                signal->restore_settings(settings);
                settings.endGroup();
        }
+
+       if (settings.contains("v_offset")) {
+               saved_v_offset_ = settings.value("v_offset").toInt();
+               set_v_offset(saved_v_offset_);
+               scroll_needs_defaults_ = false;
+               // Note: see resizeEvent() for additional information
+       }
 }
 
 vector< shared_ptr<TimeItem> > View::time_items() const
@@ -798,7 +812,7 @@ void View::update_scroll()
                vscrollbar->setRange(extents.first - areaSize.height(),
                        extents.second);
 
-       if (scroll_needs_defaults)
+       if (scroll_needs_defaults_)
                set_scroll_default();
 }
 
@@ -813,15 +827,6 @@ void View::set_scroll_default()
 
        const QSize areaSize = viewport_->size();
 
-       // Special case: when starting up and the window isn't visible yet,
-       // areaSize is [0, 0]. In this case we want to be called again later
-       if (areaSize.height() == 0) {
-               scroll_needs_defaults = true;
-               return;
-       } else {
-               scroll_needs_defaults = false;
-       }
-
        const pair<int, int> extents = v_extents();
        const int trace_height = extents.second - extents.first;
 
@@ -833,6 +838,11 @@ void View::set_scroll_default()
        else
                // Put the first trace at the top, letting the bottom ones overflow
                set_v_offset(extents.first);
+
+       // If we're not sure whether setting the defaults worked as
+       // the window wasn't set up entirely yet, we want to be called
+       // again later to make sure
+       scroll_needs_defaults_ = !size_finalized_;
 }
 
 void View::update_layout()
@@ -956,6 +966,27 @@ bool View::eventFilter(QObject *object, QEvent *event)
 void View::resizeEvent(QResizeEvent*)
 {
        update_layout();
+
+       // This is somewhat of a hack, unfortunately. We cannot use
+       // set_v_offset() from within restore_settings() as the view
+       // at that point is neither visible nor properly sized.
+       // This is the least intrusive workaround I could come up
+       // with: set the vertical offset (or scroll defaults) when
+       // the view is visible and resized to its final size.
+       // Resize events that are sent when the view is not visible
+       // must be ignored as they have wrong sizes, potentially
+       // preventing the v offset from being set successfully.
+
+       if (isVisible())
+               size_finalized_ = true;
+
+       if (size_finalized_ && saved_v_offset_) {
+               set_v_offset(saved_v_offset_);
+               saved_v_offset_ = 0;
+       }
+
+       if (size_finalized_ && scroll_needs_defaults_)
+               set_scroll_default();
 }
 
 void View::row_item_appearance_changed(bool label, bool content)
@@ -1161,11 +1192,11 @@ void View::signals_changed()
                }
 
        // Add and position the pending top levels items
+       int offset = v_extents().second;
        for (auto item : new_top_level_items) {
                add_child_item(item);
 
                // Position the item after the last item or at the top if there is none
-               int offset = v_extents().second;
                const pair<int, int> extents = item->v_extents();
 
                if (item->enabled())